Presentation
Persistent fatigue and recurrent fever. New-onset subcutaneous masses and erythematous plaques.
Patient Data
PET-CT prior to chemotherapy
PET/CT demonstrates diffuse, innumerable inflammatory changes in the superficial soft tissues, with areas of intense FDG uptake seen in areas of marked inflammatory change.
There is evidence of mild hepatosplenomegaly as well as prominent cervical, axillary, retroperitoneal, pelvic, and inguinal chain lymph nodes without a major increase in FDG avidity.
Moderate gynecomastia without an increase in FDG avidity.
A complete blood count revealed pancytopenia. An incisional biopsy was performed on an FDG-avid nodule in the hypogastric region.
Histology:
The biopsy specimen demonstrates sheets of lymphoid cells localizing to the subcutaneous tissue. These cells exhibit marked cytologic atypia: nuclear irregularity, scant cytoplasm, and numerous mitotic and apoptotic figures.
The lymphoid cells indicate the following immunophenotype:
Positive for: CD3, CD56, TIA-1, TCR-gamma, and CD45RB
Negative for: CD2, CD5, CD7, CD4, CD8, CD10, TdT, TCR-BF1, CD20, CD79a, CD138, CD163, BCL-6, MUM-1, CD34, CD117, MPO, and EBV
Final diagnosis: primary cutaneous gamma-delta T-cell lymphoma (PCGDTCL)
PET-CT after chemotherapy
PET/CT demonstrates a complete metabolic response to chemotherapy with normalization of FDG uptake in the superficial soft tissues. There is also an improved appearance of soft tissue inflammatory fat stranding when compared to the prior study.
There is diffuse skeletal FDG uptake, which may be seen in the setting of G-CSF therapy.
Case Discussion
Primary cutaneous gamma-delta T-cell lymphoma (PCGDTCL) represents a minority of cutaneous T-cell lymphoma cases 5.
Primary cutaneous lymphomas may demonstrate nodular opacities with increased FDG avidity on PET-CT 1. However, the diagnosis of PCGDTCL relies on the identification of lymphoid cells expressing a characteristic immunophenotype.
PCGDTCL is most frequently described as rapidly progressive and poor in prognosis 2,3, with some sources reporting median survival times as low as 15 months 4. The optimal therapeutic regimen has not been elucidated due to the rarity of the disease and the lack of clinical trials.
This patient case demonstrates PET-CT evidence of PCGDTCL responsiveness to an induction chemotherapy regimen of ifosfamide, carboplatin, and etoposide.
Acknowledgements: I would like to recognize Rutger S. Gunther, MD, MPH, for assisting in the creation of this case study, as well as Brooke Army Medical Center and its staff for rendering exceptional patient care and allowing review of their documentation.
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